1. Technical Field
The present invention is related generally to furnaces for casting metal and the method of using such furnaces. More particularly, the furnace is configured for the continuous casting, especially of metals such as titanium which when hot are reactive with oxygen. Specifically, the furnace includes a cutter for cutting a metal casting within the furnace and withdrawal chamber which facilitate a virtually nonstop casting process.
2. Background
There are many known configurations of continuous casting furnaces. For example, U.S. Pat. No. 7,470,305 granted to Jackson et al. discloses a furnace configured for alternating pouring from a common hearth into two continuous casting molds to form ingots in an alternating fashion, wherein two lifts are used in an alternating fashion for lowering the ingots into two separate withdrawal chambers. Each withdrawal chamber can be selectively shut off from the melting chamber in which the hearth and molds are disposed. Each withdrawal chamber has a door which can be opened to allow for the removal of the respective ingots therefrom. While the Jackson furnace provides for substantially continuous casting by the alternating pouring method, this furnace thus requires two molds, torches for each mold, two withdrawal chambers and two lifts. In addition, the Jackson furnace uses ram lifts which extend substantially below the withdrawal chambers and thus require additional vertical space for operation.
Titanium and certain other metals when hot are highly reactive with oxygen. Thus, it is desirable when casting such metals to prevent exposure of the heated ingots to air outside the furnace. U.S. Pat. No. 7,484,549 granted to Jacques et al. discloses a continuous casting furnace for casting such reactionary metals using a glass or other coating on the ingot to protect the hot ingot from exposure to oxygen after exiting the furnace chamber. While such a coating does prevent exposing the hot ingot to oxygen, this method requires a configuration for applying the glass coating and controls to properly apply the coating to the ingot. In addition, it may be desirable in certain instances to produce an ingot free from a glass or other coating on the outer perimeter of the ingot.
There is a need in the art for a relatively low cost furnace which provides for high efficiency continuous casting. The present invention provides such a furnace while eliminating various structure and processes involved with other prior art furnaces such as those discussed above.